Infectious disease
Abstract
Autophagy is a critical host defense mechanism that restricts intracellular pathogens such as Mycobacterium tuberculosis (Mtb). A key step in this process is the ubiquitination of Mtb or Mtb-associated structures. The E3 ligase SMURF1 catalyzes K48-linked ubiquitination, promoting bacterial clearance. However, the function of its homolog, SMURF2, in host defense remains undefined. Here, we demonstrate that Smurf2 deletion in murine macrophages increases SMURF1 levels, enhances LC3B lipidation, augments K48 ubiquitination of Mtb-associated structures, and reduces intracellular Mtb replication. These effects are reversed by Smurf1 deletion, supporting a role for SMURF1 in SMURF2-dependent control of Mtb. Mice with myeloid-specific Smurf2 deletion exhibit modestly prolonged survival following aerosol Mtb infection. In human macrophages, SMURF2 knockdown or its pharmacological inhibition with the HECT E3-ligase inhibitor Heclin reduces Mtb replication. Together, our findings identify SMURF2 as a negative regulator of macrophage control of Mtb and support further investigation of SMURF2 as a potential target for host-directed therapy in tuberculosis.
Authors
Priscila C. Campos, Kathryn C. Rahlwes, Victoria A. Ektnitphong, Beatriz R.S. Dias, Kubra F. Naqvi, Samuel Alvarez-Arguedas, Michael U. Shiloh
Abstract
Despite widespread vaccination, Bordetella pertussis (Bp) cases are resurging globally. Although CD4+ T cells are known to be essential for sustained protection, the antigens they recognize are not fully characterized, hindering vaccine refinement. Using immunopeptidomics, bioinformatics, and functional T cell assays, we identified high-affinity epitopes from reference and clinical Bp strains presented on MHC-II I-Ab. A subset of these epitopes stimulated systemic and mucosal CD4+ T cells of mice immunized with heat-killed Bp, and peripheral blood T cells from humans vaccinated with the whole-cell pertussis vaccine. Mice immunized with a subunit vaccine comprising two recombinant proteins identified in our screen were subsequently challenged with Bp. Bacterial burden was nearly eliminated from the lower respiratory tract and significantly reduced in the upper respiratory tract. Th1/Th17-polarized CD4+ tissue-resident memory T cells (Trms) were induced in nasal and pulmonary tissues. Depleting memory CD4+ T cells before challenge abolished protection, confirming that antigen-specific CD4+ T cells are critical for clearing Bp from the respiratory tract. Our integrated antigen identification and T cell assay approach revealed previously untested Bp antigens that elicit protective CD4+ T cell–mediated immunity, suggesting that incorporating them into new vaccines may help curb the resurgence of pertussis.
Authors
Mohamed M. Shamseldin, Jesse M. Hall, Griffin M. Lawrence, Gabrielle M. Hernandez, Yue Liu, Alexa R. Aubrey, Eva K. Verzani, Rajendar Deora, Amy Lovett-Racke, Jennifer G. Abelin, Purnima Dubey
Abstract
Clinical immunity to malaria develops after repeated malaria episodes. In this process, the inflammatory response is modulated to respond less vigorously upon reinfection. Monocytes are a major source of pro-inflammatory mediators during blood-stage infection and are known to adapt to repeated pathogen exposure. Here, we investigated the impact of previous malaria exposure on monocytes during blood-stage malaria by comparing the response in previously exposed and primary infected individuals. We observed reduced levels of several proinflammatory chemokines in previously exposed individuals, linked to changes in monocytes. Similarly, BAFF levels were lower in these individuals and associated with modulation of monocyte and dendritic cells. This affected the BAFF-BAFF-R axis, crucial for B cell responses, correlating with increasing parasite-specific antibody levels. Collectively, we present insights into how previous malaria exposure shapes monocyte responses during acute malaria and how these in turn correlate with modulation of the B cell compartment and humoral immune response.
Authors
Maximilian Julius Lautenbach, Pengjun Xi, Linn Kleberg, Alan-Dine Courey-Ghaouzi, Maia Serene Gower, Carolina Sousa Silva, Felicia Chammas, Anna Färnert, Christopher Sundling
Abstract
Mycobacteriumtuberculosis (Mtb), the causative agent of tuberculosis (TB), is the most common coinfection in people living with HIV-1 (PLWH). This coinfection is associated with accelerated HIV-1 disease progression and reduced survival. However, the immunological and virological mechanisms driving this progression are not completely understood. To address this knowledge gap, using pleural effusion samples from PLWH and TB, we investigated how the HIV-1 genetic landscape and the anti-HIV-1 immune response are impacted by a TB-associated microenvironment. Our results revealed an enrichment of genetically intact HIV-1 and impaired CD8+ T cell-mediated antiviral response at this site of HIV-1/Mtb coinfection. Moreover, efficient CD8+ T cell activation was inhibited by lipids present in the TB-associated pleural effusion. These findings indicate that this immune microenvironment induced by TB promotes the persistence of cells infected with replication-competent HIV-1 by creating a niche of reduced antiviral immune pressure, potentially contributing to the worsened clinical outcomes observed in PLWH and TB.
Authors
Samantha Cronin, Jennifer Simpson, Andrea Pereyra-Casanova, Yuchen Li, Josefina Marín-Rojas, Freja A. Warner van Dijk, Katie Fisher, Daniel J. Buffa, Hafsa Rana, Zoï Vahlas, Joaquina Barros, Mariano Maio, Thomas R. O'Neil, Kirstie M. Bertram, Eunok Lee, Najla Nasr, Andrew N. Harman, Gabriela Turk, Maria Florencia Quiroga, Anthony D. Kelleher, Christel Vérollet, Luciana Balboa, Sarah Palmer, Gabriel Duette
Abstract
Plasmodium falciparum sporozoite (PfSPZ) vaccines, comprised of aseptic, purified, live parasites that arrest during or just after liver stage development, show excellent safety and efficacy in humans. They can induce complete protection against Pf infection, mediated primarily by cellular immune responses against parasite antigens expressed in hepatocytes. Current PfSPZ vaccines rely on the West African PfNF54 parasite, which uniquely produces high numbers of PfSPZ in mosquitoes, facilitating manufacturing efficiency. However, PfNF54 has relatively low hepatocyte infectivity, limiting potency. We created hybrid pan-African Pf strains by genetically crossing PfNF54 with East African Pf strains. The hybrid, AV27, was selected for development based on balanced contribution of parental genomes, high PfSPZ production and high liver stage infectivity. As compared to NF54-based PfSPZ vaccines, we expect AV27-based vaccines will have greater and broader efficacy at lower doses due to higher liver stage infectivity and inclusion of unique East African CD8+ T cell epitopes.
Authors
Lucia Pazzagli, Bethany Jenkins, Ankit Dwivedi, Asha Patil, Yonas Abebe, Tales V. Pascini, Urvashi Rai, Priya Gupta, Nastaran Rezakhani, Chakshu Gandhi, Yiwei Yang, Sudhir Kumar, Mohd Kamil, Gigliola Zanghí, Manuel Llinás, Stephen L. Hoffman, Joana C. Silva, Ashley M. Vaughan, B. Kim Lee Sim
Abstract
CFTR in the lung epithelium contributes to the secretion of a surface liquid layer that is essential to lung homeostasis and defense. The understanding of how liquid is secreted in the lung is derived largely from studies of the airway epithelium. Comparatively little is known about liquid secretion mechanisms in the alveolar epithelium, including its cellular source. To define which cell type drives alveolar liquid secretion, we generated transgenic mice that expressed a Cftr null allele in alveolar type 1 (AT1) cells, type 2 (AT2) cells, or both, then viewed liquid secretion in live alveoli using confocal microscopy of isolated, perfused lungs. Our findings show liquid secretion was blocked in alveoli of all three transgenic mice, indicating that both AT1 and AT2 cells contribute to alveolar liquid secretion. Cftr null expression in AT1 cells also blocked the secretion-mediated clearance of small particle and bacterial clusters from alveolar walls, indicating that AT1 cell CFTR contributes to alveolar defense. Together, these findings show alveolar liquid secretion depends on both AT1 and AT2 cell CFTR, and that CFTR in AT1 cells – a cell type not traditionally considered in liquid secretion mechanisms or CFTR-related lung diseases – contributes to lung liquid dynamics and host defense.
Authors
Sayahi Suthakaran, Sonya Homami, Deebly Chavez, Stephanie Tang, Sarah K.L. Moore, Chaya Sussman, Jimmy Zhang, Clemente J. Britto, Alice Prince, Alison J. May, Jaymin J. Kathiriya, Jaime L. Hook
Abstract
Authors
Ian A. Mellis, Madeline Wu, Kristin Daniel, Hsiang Hong, Yicheng Guo, David D. Ho
Abstract
Neonatal sepsis is a predominant cause of neonatal mortality and long-term morbidity which severely effects preterm and low birth weight newborns. Antibiotic resistance and long-term developmental issues associated with neonatal sepsis necessitates finding new and improved treatment options. Interleukin-27 (IL-27) has diverse influences on the immune response, is elevated during the neonatal period compared to adulthood, and continues to rise further during infection. Elevated levels of IL-27 early in life predispose the host to impaired control of the pathogen burden and increased mortality. This study explored the therapeutic potential of IL-27p28 antibody administration to improve treatment outcomes during murine neonatal sepsis. Sepsis was induced by subcutaneous inoculation of K1-encapsulated Escherichia coli and the neonatal pups were rescued with IL-27p28 monoclonal antibody. Pups that received prophylactic antibody prior to the infection demonstrated superior bacterial clearance and significant weight gain compared to controls during infection. The combination of subclinical dose of gentamicin and IL-27p28 antibody administered 2h post-infection, significantly improved bacterial clearance, glucose homeostasis, with reduced serum levels of IL-6 and TNF-α, vital organ damage and significantly improved the survival rate of infected pups compared to gentamicin alone. These findings suggest that IL-27p28 antagonization represents a promising therapeutic tool for treatment of neonatal sepsis.
Authors
Madhavi Annamanedi, Jessica M. Povroznik, Samantha Arevalo-Marcano, Cory M. Robinson
Abstract
Single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) has enhanced our understanding of host immune mechanisms in small cohorts, particularly in diseases with complex and heterogeneous immune responses such as sepsis. However, standard PBMC isolation from blood requires technical expertise and over two hours of onsite processing using Ficoll density gradient separation (‘Ficoll’) for scRNA-seq compatibility, precluding large-scale sample collection at most clinical sites. To minimize onsite processing, we developed Cryo-PRO (Cryopreservation with PBMC Recovery Offsite), a method of immediate onsite whole blood cryopreservation and subsequent batched PBMC isolation in a central laboratory prior to sequencing. We compared multimodal single-cell immune profiling results from samples processed using Cryo-PRO versus standard onsite Ficoll separation in 23 patients with sepsis. Critical outputs including cell substate fractions, marker genes, and surface protein expression were similar for each method across multiple cell types and substates, including an important monocyte substate enriched in patients with sepsis. Capture of T cell receptor transcripts was also comparable across both methods. Cryo-PRO reduced onsite sample processing time from >2 hours to <15 minutes and was reproducible across two enrollment sites, thus demonstrating potential for expanding multimodal single-cell analyses in multicenter studies of sepsis and other diseases.
Authors
Alyssa K. DuBois, Pierre O. Ankomah, Alexis C. Campbell, Renee Hua, Olivia K. Nelson, Christopher A. Zeuthen, M. Kartik Das, Shira Mann, Abigail Mauermann, Blair A. Parry, Nathan I. Shapiro, Michael R. Filbin, Roby P. Bhattacharyya
Abstract
The estrogen receptor is hypothesized to directly influence HIV-transcription and latency but is also critical for immune signaling. However, the mechanisms of action of the estrogen receptor (ER) in immune cells in the context of HIV are limited, and relevant to HIV cure strategies, the influence of latency reversal agents (LRAs) on the ER pathway are unknown. We evaluated a) the impact of estrogen (E2) on the nuclear translocation of estrogen receptor α (ERα) in CD4+ T cells, b) the ability of Fulvestrant, a selective estrogen receptor degrader (SERD), and ARV-471, a novel, potent, PROteolysis TArgeting Chimera (PROTAC) selective ERα degrader to modulate ER and c) the impact of different classes of LRAs on ER signaling. In contrast to what has been demonstrated in oncology, E2 does not induce ERα nuclear translocation in CD4+ T cells. Similarly, neither Fulvestrant nor ARV-471 induced degradation of ERα in CD4+ T cells. LRAs significantly downregulated ERα gene and protein expression in both PBMCs and CD4+ T cells. Collectively, our results suggest that estrogen influences on HIV transcription are not likely a consequence of canonical nuclear ERα mechanisms. The consequences of LRA downregulation of ER, a protein important for immune signaling, warrants further investigation.
Authors
Cristina Ceriani, Priya Khetan, Anthony Abeyta-Lopez, Kena J. Lemu, Prachi Meher, Brigitte Allard, Katherine S. James, Anne-Marie W. Turner, David M. Margolis, Nancie M. Archin
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